|Quadrangle map, 1:250,000-scale||MC|
|Quadrangle map, 1:63,360-scale||B-4|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This occurrence is on the ridge crest between Twaharpies Glacier and Canyon Creek. It is at elevation 7470 in the NW1/4 of section 22, T. 6 S., R 18 E. of the Copper River Meridian. This is locality 46 of MacKevett (1976); the location is accurate to within about 100 feet.|
Geologic descriptionThis occurrence consists of a 6-foot-wide fault zone that contains narrow veins with chalcocite and malachite (MacKevett and Smith, 1968; MacKevett, 1976). A sample of the mineralization contained up to 7 parts per million (ppm) silver, 1,000 ppm arsenic, and more than 20,000 ppm copper. The fault zone cuts Triassic Nikolai Greenstone (MacKevett and Smith, 1972). Copper mineralization is common in Nikolai Greenstone and is thought to have accompanied regional deformation and low-grade metamorphism in the Late Jurassic to Early Cretaceous (MacKevett and others, 1997).
|Geologic map unit||(-142.177340372222, 61.336483759861)|
|Mineral deposit model||Basaltic Cu (Cox and Singer, 1986; model 23)|
|Mineral deposit model number||23|
|Age of mineralization||Cretaceous? Copper mineralization is common in Nikolai Greenstone and is thought to have accompanied regional deformation and low-grade metamorphism in the Late Jurassic to Early Cretaceous (MacKevett and others, 1997).|
|Alteration of deposit||Oxidation.|
|Workings or exploration||Only limited surface sampling.|
|Indication of production||None|
Additional commentsThe locality is in the Wrangell-Saint Elias National Park and Preserve.
MacKevett, E.M., Jr., 1976, Mineral deposits and occurrences in the McCarthy quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-773-B, 2 sheets, scale 1:250,000.
MacKevett, E.M., Jr., and Smith, J.G., 1968, Distribution of gold, copper, and some other metals in the McCarthy B-4 and B-5 quadrangles, Alaska: U.S. Geological Survey Circular 604, 25 p.
MacKevett, E.M., Jr., and Smith, J.G., 1972, Geologic map of the McCarthy B-4 quadrangle, Alaska: U.S. Geological Survey Geologic Quadrangle Map GQ-943, 1 sheet, scale 1:63,360.
MacKevett, E.M., Jr., Cox, D.P., Potter, R.W., III, and Silberman, M.L., 1997, Kennecott-type deposits in the Wrangell Mountains, Alaska--High-grade copper ores near a basalt-limestone contact, in Goldfarb, R.J., and Miller, L.D., eds., Mineral deposits of Alaska: Economic Geology Monograph 9, p. 66-89.
|Reporters||Travis L. Hudson (Applied Geology, Inc.)|
|Last report date||1/12/2003|